I use Google Apps for my domain email, and I was wondering if I could use that account for OpenID instead of the regular Gmail account.
I know I can delegate Openid
For OpenId2 I currently have this on my site
<link rel="openid2.provider" href="https://www.google.com/accounts/o8/ud" />
as it is the only one required. Since I am logged in to Google Apps now as my default google account. OpenID consumers (Stack Exchange Sites mostly at this point) use that account (I get a message from google asking if the site can use that google account.
This doesn't FORCE the google apps account the way it would if you used a non-google apps account with (in addition to the provider above)
<link rel="openid2.local_id" href="http://www.google.com/profiles/YOURGOOGLEPROFILE" />
But it does allow me to use my google apps account because it is the one I am currently logged in with.
They say they will in the future but doesn't give any clue to when the future will be here. See this thread in Google groups http://groups.google.com/group/google-federated-login-api/browse_thread/thread/19b33847210e5708
MyOpenID.com does offer openid on your own domain.
Google recently (an hour or so ago) announced OpenID support for Google Apps customers.
Check out the discovery protocol on Google Groups. Should be a good start.
I believe the endpoint is ht tps://www.google.com/accounts/o8/site-xrds?hd=your-domain.com
My understanding is that Google is not exposing that server url, and as such makes this technique inoperable for a Google OpenID.
You can run your own openid server in your Google Apps domain (using GAE) - Google provides sample code of openid server. I've recently ported this to latest OpenID library, so now it is Openid 2.0 compatible. Project page: http://code.google.com/p/appengine-openid-provider/